Hummingbirds, with their shimmering feathers and rapid wingbeats, are a source of fascination for many. Their attraction to red is often observed at garden feeders and in natural settings. This preference is rooted in their unique biology and evolutionary history. Understanding this attraction reveals insights into their sensory world and relationship with flowering plants.
Hummingbird Vision and Color Perception
Hummingbirds perceive colors in ways humans cannot. Unlike humans, who have three types of color-sensitive cones for red, green, and blue light, hummingbirds have a fourth cone type that detects ultraviolet (UV) light. This gives them tetrachromatic vision, allowing them to see colors invisible to the human eye, including combinations like ultraviolet+green and ultraviolet+red. Their retinas also feature a denser concentration of cones, enhancing sensitivity to warmer shades like red and yellow, while muting cooler colors such as blue.
Hummingbirds distinguish “nonspectral” colors, combinations of light from widely separated parts of the spectrum. For instance, they can differentiate ultraviolet+green from pure green, even when these colors appear identical to human observers. This ability helps them navigate their environment and efficiently locate resources. The presence of oil droplets in their cones further refines color sensitivity, acting like filters that heighten perception of colors in the red to yellow range.
The Evolutionary Link to Nectar-Rich Flowers
The strong attraction hummingbirds have to red is largely a result of co-evolution with flowering plants. Many hummingbird-pollinated flowers display vibrant red or orange hues, signaling available nectar. These plants have evolved tubular shapes suited for a hummingbird’s long beak and tongue, making nectar difficult for other pollinators to reach. This specialized relationship ensures that hummingbirds act as efficient pollinators, carrying pollen from one flower to another as they feed.
Red flowers often provide a higher concentration of sucrose-rich nectar, which hummingbirds need to fuel their active metabolism. This provides a significant energetic reward, reinforcing their preference for these colors. Insects, major competitors for nectar, generally do not see red as well as hummingbirds. This visual difference means red flowers are less appealing to many insects, leaving more nectar exclusively for hummingbirds and reducing competition.
Beyond Red: Other Attractors and Practical Applications
While red is a powerful attractant, hummingbirds are not limited to this single color. They are also drawn to other bright hues like orange, pink, purples, and yellows. These colors stand out in natural landscapes, signaling nectar sources. Studies show hummingbirds are almost as attracted to orange as red, and pink flowers with UV-reflecting properties are effective.
For individuals interested in attracting hummingbirds, practical applications of this knowledge are abundant. Using red hummingbird feeders is an effective strategy, as the color serves as a strong visual cue. Planting a variety of brightly colored, tubular flowers in shades of red, orange, and pink creates an appealing habitat. Ensuring a consistent nectar supply, either through natural blooms or feeders, encourages regular visits.